diff --git a/app.js b/app.js
index 1726d53..c7b1fb1 100644
--- a/app.js
+++ b/app.js
@@ -1,28 +1,48 @@
-const express = require('express')
-const siteMap = require('./siteMap')
+const express = require('express');
+// A genareted db with all the pages
+const siteMap = require('./siteMap');
+// All compilers for all page source types
 const compile = require('./compile');
 const settings = require('./settings');
-const { render } = require('ejs');
 
-console.log(siteMap)
+console.log("siteMap:", siteMap) //DEBUG
 
+// create webserver
 const app = express()
 app.set('view engine', 'ejs');
 app.set('views', __dirname + '/views')
 
+//TODO: make the uri routing more universal. Probebly ad the siteMap creation
+// routing
 app.use('/:vak/static', renderStatic)
 app.use('/:vak/:page', renderPage)
 app.use('/:vak', renderVak)
 app.use('/', renderIndex)
 app.use(render404)
 
-
+/** This function can be used for as callback for errors
+ * 
+ * @param {Req} req Request object from Express.
+ * @param {Res} res Responce object from Express.
+ * @param {Function} next The next function from Espress.
+ * 
+ * @returns {Function(err)} a function that renders the 404 page if err is true.
+ */
 function onError404(req, res, next){
   return function(err){
-    render404(req, res, next)
+    if(err)
+      render404(req, res, next)
   }
 }
 
+/** Render static content
+ * 
+ * looks for the content in the folder static
+ * 
+ * @param {Req} req Request object from Express.
+ * @param {Res} res Responce object from Express.
+ * @param {Function} next The next function from Espress.
+ */
 function renderStatic(req, res, next){
   if(typeof siteMap[req.params.vak] == 'undefined') return next();
   vak = siteMap[req.params.vak]
@@ -33,6 +53,14 @@ function renderStatic(req, res, next){
   res.sendFile(dir, onError404(req, res, next))
 }
 
+/** Render a normal page
+ * 
+ * lookup the page in siteMap db and renders the page
+ * 
+ * @param {Req} req Request object from Express.
+ * @param {Res} res Responce object from Express.
+ * @param {Function} next The next function from Espress.
+ */
 function renderPage(req, res, next){
   if(typeof siteMap[req.params.vak] == 'undefined') return next();
   vak = siteMap[req.params.vak]
@@ -55,17 +83,26 @@ function renderPage(req, res, next){
   })
 }
 
+/** Render the index of a topic
+ * 
+ * lookup the topic in siteMap db and renders the index.
+ * if the index is not set it set the topic name as headers on the page.
+ * 
+ * @param {Req} req Request object from Express.
+ * @param {Res} res Responce object from Express.
+ * @param {Function} next The next function from Espress.
+ */
 function renderVak(req, res, next){
   if(typeof siteMap[req.params.vak] == 'undefined') return next();
   vak = siteMap[req.params.vak]
 
-  if(vak.index == null){
+  if(vak.index == null){ // no index page for this topic
     res.render('main', {
       siteMap,
       title: "notes",
       topNav: vak.pages,
       vak: req.params.vak,
-      main: `<h1>${vak.title}</h1>`
+      main: `<h1>${vak.title}</h1>` // default index page
     })
   }else{
     compile(vak.index, function(html){
@@ -82,6 +119,16 @@ function renderVak(req, res, next){
   }
 }
 
+//TODO: remove playholder and acualy create the renderIndex function
+/** Render the index of the site
+ * 
+ * lookup the index in siteMap db and renders the index.
+ * if the index is not set it set the topic name as headers on the page.
+ * 
+ * @param {Req} req Request object from Express.
+ * @param {Res} res Responce object from Express.
+ * @param {Function} next The next function from Espress.
+ */
 function renderIndex(req, res, next){
   res.render('main', {
     siteMap,
@@ -91,6 +138,15 @@ function renderIndex(req, res, next){
   }, onError404(req, res, next))
 }
 
+//TODO: add a custom or smarter 404 page
+/** Render the 404 page
+ * 
+ * renders a simple 404 page.
+ * 
+ * @param {Req} req Request object from Express.
+ * @param {Res} res Responce object from Express.
+ * @param {Function} next The next function from Espress.
+ */
 function render404(req, res, next){
   res.status(404)
   res.render('main', {
@@ -106,4 +162,5 @@ function render404(req, res, next){
   })
 }
 
-app.listen(settings.serverPort, ()=>{console.log("server listening on", settings.serverPort)})
+// start the actial web server
+app.listen(settings.serverPort, ()=>{console.log("server listening on port", settings.serverPort)})
diff --git a/siteMap.js b/siteMap.js
index d0b4ddc..d2094d6 100755
--- a/siteMap.js
+++ b/siteMap.js
@@ -56,13 +56,13 @@ function scanDirectory(file, path){
   }
 
   return {
-    title: file,
+    title: String (file),
     type: "directory",
-    file: path,
+    file: String (path),
     index: (index) ? index : {
-      title: file,
+      title: String (file),
       type: 'index',
-      file: path
+      file: String (path)
     },
     subPages: scanPages(path, files)
   }